Process for making thin metallic flakes.



our-rm) STATES PATENT oF-Fion.

THOMAS A: EDISON, Ol" LLEWELLYX PARK.

STORAGE BATTERXZ -COMPAN Y, OF WEST OR JERSEY.

ORANGE, XEW JERSEY, ASSIGXOR TU EDlbON AXGE, NEW JERSEY, A CORPORATIONOI NEW PROCESS FOR MAKING THIN METALLIC FLAKES.

Original application filed March 30, 1905. Seiial No. 252. Serial No.

To all whom it may concern:

Be it known that I, T noitAs ALVA Emsozv,

a citizen of the United States, residing at -very thin metallic flakeswhich are suitable for use in forming the active material of my improvedstorage battery and more particularly to the formation of flakes of thischaracter, which consist of a new productbroadly claimed in my PatentNo. 850,881 granted April 16, 1907. This is a division of Patent- Xo.827,717, above referred to, Patent No. 50,881 is entitledcompositemetal, and in the disclosure thereof two or more metals arephysically admixed in such a way that each metal exists as apracticallyintegral spongelike structure, the cells or pores of eithermetal being completely filled by the body presented by the other metal,whereby the entire bulk of the composite structure as a. whole will becontinuously solid throughout. Such a composite metal ischaracteristically distinguished from any so-called alloy heretofoi-emade, so far as I know, in the respect that it consists of sponge-likeinterlocking masses, so that itbecomes possible by dissolving orotherwise removing one of the metals to'obtain a sponge-like integralmass of the other metal, whereas, with ordinary alloys, owing to theirintimate molecular admixture, the attempt to dissolve any one of theconstituents of the alloy results in the disintegration of the mass.This characteristic peculiarity of my improved composite 'metal makes itpossible to secure very beautiful sponge-like effects in various metals,by first forming the composite metal and then removing one of themetals, and it also becomes possible to secure attractive efi'ects inmany arts, where it is desirable that two or more metals should bemechanically associated together.

The-primary purpose for which I have used the composite metal referredto is for the production of scales, flakes or foils of nickelSpecification of Letters Patent.

Patented March 2, 1909.

933. Divided and. this application filed July 14. 1906.

and cobalt for admixture with the active material in the negativeelectrode of my improved storage battery. As I have pointed outin myPatent No. 857,929, granted June 25, L907, good contact with such activematerial and bet-ween the flakes or foils themselves is secured whenmetallic cobalt is used, but as I have explained, it is undesirable touse metallic cobalt alone, owing to the fact that its surface becomesoxidized by electrolysis and might in time penetrate the whole mass, andhence it might be advisable to make use of a composite metal of cobaltand nickel. Such a composite metal serves to give excellent contact, andthe presence of the nickel therein )I'GVBIltS penetration of oxid withinthe nicikel cobalt to a harmful extent, since the metallic nickel formsa continuous integral connecting sponge, and therefore protects thecobalt from the possibility of inward oxidation to anyharmful extent.

To make a composite metal of nickel and cobalt for the purpose offorming scales, films or foils for use in the make-up of .my

fol ows:- A solution of. sulfate ofnickel'and sulfate of cobalt is firstobtained in the proper relative quantity to give the resulting productthe desired pro ortions of the two metals. Excellent resu ts have beensecured with a composite metal containing vper cent. of cobalt and 40per cent. of nickel,

ut these proportions may be varied within quite wide limits. Thesolution of cobalt and nickel sulfates is now added to apotash solutionin excess of that necessary to precipitate the two salts and the twosolutions thus added are boiled, resulting in the precipitation ofhydroxids of nickel and cobalt, which are allowed to settle. Thesolution is now drawn oil and the precipitated mixed hydroxids arewashed successively until the mass is free of potash and sulfates. Inthis way I obtain a physically and intimately improved battery, Iproceedsubstantially as mixed mass of hydroxids of the two metals 1granules are subjected to the reducing action by hydrogen gas in aheated retort to reduce the hydroxide to the respective metals and alsoto weld together the metallic particles constitutin teristics beforepointed out. The reduced 'metallic granules are now subjected-to suc-- jcessive rolling operations with oil to convert the composite metal intofine scales or flakes I as is common in the art, for example, of makmgbronze powder. Preierably the flakes are annealed two or more timesbetween the passes of the rolling operation in an inert or n0noX1d1z1nggas, such as hydrogen, at a red heat. After the flakes or foils areformed it is desirable, in order to increase their bulk,

fli -to pass them between very rolls by which they will be crimped,corrugated or otherwise distorted, or between rolls of very smalldiameter by which they 5 will be curled or formed into minute spirals.

These flakes or foils are added to the active -material of, the batteryin any suitable way,

in my Patents No. 882,144, granted March 17, 1908 for example, as I havedescribed and No. 854,200, granted May 21, 1907,

-wherein the conducting flakes are first as- E sembled and then weldedto constitute a 5 s onge-like or honeycomb structure in which tlieactive material is introduced by successively dipping the same into asaturatedsolution of the active salt and alternate evapo ration of thesolvent. Or instead, the active particles may be coated with a stickymate- 5 rial such as molasses, and then admixed with the metallic'flakesor scales, being then as- 1 sembled in the pockets, a moderate pressureapplied, the molasses being then dissolved out and the final pressureapplied, as I de fine crimping No. 839,371, granted i does not reactthereupon,'between one or p more of the passes, substantially as setforth. 2. The process of-making very thin me tallic flakes whichconsists in obtaining Q granules vcomposed of two or more metals each inthe form of a substantiall Y integral i sponge-like structure, saidstructures being engaged intimately together to constitute a solid mass,subjecting said metallic granules i to successive rolling operations andanneal-. ing the same in a gas which does not react 5' thereupon afterone or more of the rolling operations, substantially as set forth.

3. T he process of making'very thin metallic flakes which consists inobtaining granules composed of cobalt and nickel each I in the form of asubstantiallyintegral spongelike structure intimately'engaging togetherto form a continuous solid mass, subjecting said granules to successiveY rolliLg operations, and annealing the same in a gas which does notreact thereupon after one or more i set forth. This specification signedand witnessed this 13th day of July 1906. 1 THOS. AJEDISON.

lVitnesses:

- GRANT L. DYER,

ANNA R. KLEHM.

f the rolling operations, substantially asv

